An Auger electron spectroscopy (AES) study of the initial stages of oxidation of the single crystal Be (0001) surface

Abstract

The oxidation of Be(0001), in particular the early stages of the reaction, was tracked dynamically by AES using a computer controlled single pass CMA. The reaction was followed by monitoring the three Auger transitions, Be(KVV), BeO(KVV), and O(KVV) in dN/dE mode. Because the Be(KVV) and the BeO(KVV) signals overlap, a multiple linear regression analysis based on a linear combination of the spectra of clean, cleaved Be and a BeO crystal was done to separate them. Results have been obtained for oxygen partial pressures ranging from 4.7×10−7 Pa (3.6×10−9 Torr) to 1.3×10−4 Pa. Considerable structure is seen in the uptake curves suggesting the occurrence of multiple stages of growth. The oxidation process appears to be linearly dependent on pressure for high pressures. Further conclusions are made difficult due to the strong enhancement of the oxidation by the AES incident electron beam. Finally, at all pressures studied, an excess of oxygen signal compared to that expected from stoichiometric BeO exists in the very early stage of the oxidation.